“Printed circuit boards” (PCBs) or “printed wiring boards” (PWBs) are frequently interconnected with one another using coaxial cables in high frequency devices, circuits and subsystems, such as those operating at radio frequency (RF) and microwave frequency ranges. Coaxial connectors at an interface between a PCB and the coaxial cable allow a PCB to be connected and disconnected during assembly and/or testing, as well as for maintenance and replacement purposes once the PCB has been deployed. A variety of classes or series of standard and semi-custom coaxial connectors are readily available and in widespread use including, for example, SMA, SMB, SMC, SSMA, 3.5-mm, 2.4-mm and 1.85-mm connectors. Each of the various coaxial connector series is available in a variety of styles, each style being adapted to a particular application and/or circuit-mounting configuration.
Coaxial connectors provide an inner or signal conductor coaxially disposed within an outer conductor both having precisely controlled radii having a common axis, with the dielectric material disposed therebetween. Certain coaxial connectors are mountable to circuit boards, with the signal conductor electrically connected to a signal circuit of the board and the outer conductor electrically connected to a ground path on the board, and the electrical connections are commonly achieved by soldering. One such connector is disclosed in U.S. Pat. No. 4,650,271.
A known technique of accomplishing this is to end launch a right angle coaxial connector onto a planar surface conductor, e.g. a microstrip, along the substrate edge. In U.S. Pat. No. 5,405,267, a plurality of similar board-mountable coaxial connectors is secured to a mounting bracket that is affixed to a circuit board along an edge thereof, with each coaxial connector extending through a panel cutout at an input/output port of an electronic apparatus. Disadvantages of this approach include the relatively large space and volume requirements, and the requirement that the transition be made at the edge of the substrate.
Among the coaxial connector styles used in conjunction with high frequency PCBs are surface-mountable styles often referred to as “surface mount” (SMT) connectors. One SMT edge launch connector has a female-type SMA coaxial connector interface on one end and a center pin extending from the other end. The center pin is typically surrounded by a dielectric material, such as TEFLON, and forms a coaxial transmission structure having a characteristic impedance with the metal body of the SMT edge launch connector. Ledges extend away from the metal body to support the SMT edge launch connector in a cutout in a printed circuit board during assembly (e.g. soldering).
Corning Gilbert Inc., of Glendale, Ariz., produce a Gilbert Puny Push On (GPPO) edge mount, catalog series number B010-L, and a GPPO right angle to printed circuit board coupling, catalog series number B009-P, both of which are designed to couple a PC transmission line to a coaxial transmission line. In both cases, the component is connected to the PC transmission line, and the combined component and transmission line may then be “pushed-on” to the coaxial transmission line so that the two lines are interconnected. These connectors provide little or no strain relief and typically require RF tuning on the substrate.
There is a need in many RE systems to provide a surface mountable orthogonal transition from a PCB planar surface conductor, e.g. a microstrip transmission line or coplanar transmission waveguide, to a coaxial transmission line with sufficient strain relief and without RF tuning.